Aqueous siliocone-organic hybrids

Abstract

The present invention relates to hybrid aqueous silicone-organic composition which are prepared by first forming a silicone oil-in-water emulsion by dispersing an oil phase, containing a silicone polymer and a specific non-ionic surfactant, in a water phase containing a poly(vinyl alcohol) dissolved in water. This silicone emulsion is subsequently mixed with a an aqueous solution of a water-soluble polymer to form the instant compositions which can be applied to substrates to provide coatings having heat resistance comparable to conventional all-silicone systems delivered from organic solvent solution.

We claim: 
     
       1. An aqueous silicone-organic composition prepared by a two-step process consisting essentially of: (A) forming an aqueous silicone emulsion consisting essentially of (I) 100 parts by weight of a silicone resin;   (II) up to 50 parts by weight of a water-immiscible solvent system;   (III) one non-ionic surfactant selected from the group consisting of (a) sorbitan monoesters of carboxylic acids having 8-12 carbon atoms,   (b) polyethylene alkyl ethers having the formula   CH.sub.3 (CH.sub.2).sub.m (OCH.sub.2 CH.sub.2).sub.n OH        in which m is 7 to 15 and n is 2 to 50, and   (c) alkylphenoxy polyethoxy ethanols having the formula   C.sub.r H.sub.2r+1 (C.sub.6 H.sub.4)O(CH.sub.2 CH.sub.2 O).sub.s CH.sub.2 CH.sub.2 OH        in which r is 4 to 8 and s is 7 to 40;     (IV) poly(vinyl alcohol), the weight ratio of said poly(vinyl alcohol) (IV) to said non-ionic surfactant (III) being 0.01 to 10; and   (V) at least 10 parts by weight of water, wherein the total content of said non-ionic surfactant (III) and said poly(vinyl alcohol) (IV) is sufficient to produce a uniform oil-in-water dispersion of components (I) through (IV), and wherein said silicone resin (I) comprises at least two units selected from the group consisting of MeSiO 3/2  units, Me 2  SiO 2/2  units, PhMeSiO 2/2  units, PhSiO 3/2  units, Ph 2  SiO 2/2  units and PrSiO 3/2  units, in which Me denotes a methyl radical, Ph denotes a phenyl radical and Pr denotes a propyl radical, and said silicone resin contains up to 25% by weight of silicon-bonded moieties selected from the group consisting of hydroxyl groups and alkoxy groups having 1 to 3 carbon atoms, and     (B) mixing said aqueous silicone emulsion with an aqueous organic polymer solution comprising (VI) 100 parts by weight of a water-soluble organic polymer;   (VII) up to 15 parts by weight of a water-miscible coalescing solvent; and   (VIII) at least 50 parts by weight of water, the weight ratio of said silicone polymer (I) to said water-soluble organic polymer (VI) in said aqueous silicone-organic composition being in the range of 15:1 to 1:1.     
     
     
       2. The composition to claim 1, wherein said resin has 0.5 to 6 weight percent residual hydroxyl radicals attached to the silicon atoms thereof, a total molar organic group to silicon ratio of 1 to 1.7 and a total molar phenyl group to silicon ratio of 0.35 to 0.85. 
     
     
       3. The composition according to claim 2, wherein said non-ionic surfactant (III) is selected from the group consisting of sorbitan monolaurate, a polyethylene alkyl ether having the average formula   CH.sub.3 (CH.sub.2).sub.m (OCH.sub.2 CH.sub.2).sub.n OH     in which m is 7 and n is 4 to 23, and an alkylphenoxy polyethoxy ethanol having the average formula     C.sub.r H.sub.2r+1 (C.sub.6 H.sub.4)O(CH.sub.2 CH.sub.2 O).sub.s CH.sub.2 CH.sub.2 OH     in which r is 8 and s is 9.   
     
     
       4. The composition according to claim 3, wherein the weight ratio of said poly(vinyl alcohol) (IV) to said non-ionic surfactant (III) is 0.05 to 4. 
     
     
       5. The composition according to claim 4, wherein said silicone polymer (I) further comprises up to 5 weight percent of a polydimethylsiloxane liquid. 
     
     
       6. The composition according to claim 1, wherein said water-soluble polymer (VI) is selected from the group consisting of acrylic, polyester and alkyd polymers and copolymers. 
     
     
       7. The composition according to claim 2, wherein said water-soluble polymer (VI) is selected from the group consisting of acrylic, polyester and alkyd polymers and copolymers. 
     
     
       8. The composition according to claim 3, wherein said water-soluble polymer (VI) is selected from the group consisting of acrylic, polyester and alkyd polymers and copolymers. 
     
     
       9. The composition according to claim 5, wherein said water-soluble polymer (VI) is an acrylic polymer or copolymer. 
     
     
       10. The composition according to claim 1, wherein said water-soluble polymer (VI) is selected from the group consisting of acrylic, polyester and alkyd polymers and copolymers. 
     
     
       11. The composition according to claim 1, wherein said non-ionic surfactant (III) is selected from the group consisting of sorbitan monolaurate, a polyethylene alkyl ether having the average formula   CH.sub.3 (CH.sub.2).sub.m (OCH.sub.2 CH.sub.2).sub.n OH     in which m is 7 and n is 4 to 23, and an alkylphenoxy polyethoxy ethanol having the average formula     C.sub.r H.sub.2r+1 (C.sub.6 H.sub.4)O(CH.sub.2 CH.sub.2 O).sub.s CH.sub.2 CH.sub.2 OH     in which r is 8 and s is 9.   
     
     
       12. The composition according to claim 11, wherein said water-soluble polymer (VI) is selected from the group consisting of acrylic, polyester and alkyd polymers and copolymers. 
     
     
       13. The composition according to claim 1, wherein said non-ionic surfactant (III) is sorbitan monolaurate. 
     
     
       14. The composition according to claim 2, wherein said non-ionic surfactant (III) is sorbitan monolaurate. 
     
     
       15. The composition according to claim 10, wherein said non-ionic surfactant (III) is sorbitan monolaurate. 
     
     
       16. An aqueous silicone-organic composition prepared by a two-step process comprising: (A) forming an aqueous silicone emulsion consisting essentially of (I) 100 parts by weight of a liquid silicone polymer selected from the group consisting of polydimethylsiloxane, polyphenylmethylsiloxane, polytrifluoropropylmethylsiloxane and copolymers thereof;   (II) up to 50 parts by weight of a water-immiscible solvent system;   (III) a non-ionic surfactant selected from the group consisting of (a) sorbitan monoesters of carboxylic acids having 8-12 carbon atoms,   (b) polyethylene alkyl ethers having the formula   CH.sub.3 (CH.sub.2).sub.m (OCH.sub.2 CH.sub.2).sub.n OH        in which m is 7 to 15 and n is 2 to 50, and   (c) alkylphenoxy polyethoxy ethanols having the formula   C.sub.r H.sub.2r+1 (C.sub.6 H.sub.4)O(CH.sub.2 CH.sub.2 O).sub.s CH.sub.2 CH.sub.2 OH        in which r is 4 to 8 and s is 7 to 40;     (IV) poly(vinyl alcohol), the weight ratio of said poly(vinyl alcohol) (IV) to said non-ionic surfactant (III) being 0.01 to 10; and   (V) at least 10 parts by weight of water, wherein the total content of said non-ionic surfactant (III) and said poly(vinyl alcohol) (IV) is sufficient to produce a uniform oil-in-water dispersion of components (I) through (IV), and     (B) mixing said aqueous silicone emulsion with an aqueous organic polymer solution comprising (VI) 100 parts by weight of a water-soluble organic polymer;   (VII) up to 15 parts by weight of a water-miscible coalescing solvent; and   (VIII) at least 50 parts by weight of water, the weight ratio of said silicone polymer (I) to said water-soluble organic polymer (VI) in said aqueous silicone-organic composition being in the range of 15:1 to 1:1.     
     
     
       17. The composition according to claim 16, wherein said liquid silicone polymer is polydimethylsiloxane. 
     
     
       18. The composition according to claim 17, wherein said surfactant (III) is sorbitan monolaurate.